They aren't liked to work for. A general sense of Kate being completely out of her depth along Ma poking her snout in and barking orders doesn't make a happy household. Willy is said by all to be difficult and very petulant too, no wonder staff don't stay long. It's a good thing that equerries have a shortish timeframe as they would probably walk too. The arrival of Mrs Q was long overdue. She could probably see the damage the mooching Midds were doing too.